An ultrasonic receiver can be used to determine a location with reference to an ultrasonic emitter, such as locating a mobile device having an ultrasonic emitter and being present within a retail, factory, warehouse, or other indoor environment, for example. The ultrasonic emitter can transmit ultrasonic energy in a short burst which can be received by an ultrasonic transducer (microphone) in the ultrasonic receiver, thereby establishing at least the presence of the device within the environment. However, this requires that the mobile device have an installed ultrasonic emitter, which adds cost.
Further, the use of several ultrasonic microphones distributed within the environment can also be used to provide not only the presence but a specific location of a particular device using techniques known in the art such as triangulation, trilateration, and the like, as have been used in radio frequency locationing systems. However, this still requires that the mobile device have an installed ultrasonic emitter, which adds cost.
Accordingly, there is a need for a technique to locate a user's smart phone in an indoor environment without modifying the phone hardware and without requiring the user to carry an additional device for locationing purposes. It would also be beneficial if this technique did not require significant or complicated infrastructure changes and maintenance.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.